Combustion engines



Aug. 2a, 1923. 1,466,470

E. DODSON APPARATUS FOR CONTROLLING'THE IGNITION PdINT IN INTERNALCOMBUSTION ENGINES Filed April 15 1922 3 Sheets-Sheet 1 mam Aug. 28,1923.

' E. DODSON APPARATUS FOR CONTROLLING THE IGNITION POINT IN INTERNALCOMBUSTION ENGINES Filed April 15 1922 3 Sheets-Sheet 2 .AITTORNEYMTNESSES Aug. 28, 1923. 1,466,470

E. DODSON APPARATUS FOR CONTROLLING THE IGNITION POINT IN INTERNALCOMBUSTION ENGINES Filed April 15 1922 3 Sheets-Sheet 3 IN NTORWITAESSES umi 014m,

ATTORNEY Patented Aug. 28, 1923.

UNITED STATES PATENT OFFICE.

EDWARD DODSON, OF LONDON, ENGLAND.

Application filed April 15, 1922.

To all whom it may concern:

Be it known that I, Enwinu) DODSON, a subject of the King of England,residing at London, England, have invented certain new and usefulln'iprovements in ripparatus for Controlling the Ignition Point inInternal-Combustion Engines, of which the following is a specification.

My invention relates to apparatus for controlling the ignition point ininternal combustion engines, of the kind in which the suction effect ofthe engine is employed to advance the point of ignition against theaction of gravity or a spring tending always to retard the ignition.

It is the object of the invention so to con trol the spring effectrelatively to the suction effect that the apparatus may be as sensitiveat the open position of the throttle (when the changes of inductionpressure are relatively slight), as at the partly-closed or closedposition when they increase in magnitude.

According to this invention, means are employed to decrease the suctioneflect relatively to the gravitational or spring effect as the enginethrottle is closed and vice versa, and these means may comprise either alever (or asystem of levers), the moment of which is variable by theagency of a member displaceable along the arm of the lever to or fromits fulcrum (or this displaceablemember may itself form the fulcrum),and actuated by the movements of the engine throttle, or, inasmuch asthe closure or partial closure of the throttle valve produces acorresponding depression in the induction pipe, additionalsuction-operated apparatus may be employed to vary. the position of thelever fulcrum, instead of actuating it by a connection with the throttlevalve. )Vith either arrangement the lever, which is operativelyconnected to the ignition member, tends to turn in one direction underthe action of the engine suction, and in the opposite direction underthe act-ion of a spring or the like, and themovement of the throttle orthe action of the additional suction device acts positively to weakenthe moment of the spring, (or conversely to increase the moment of themain or primary suction device) when the throttle is fully open, andvice versa, when it istclosed.

The manner of carrying out the invention IN INTERNAL-COMBUSTION SerialNo. 553,280.

is illustrated diagrammatically by the accompanying drawings in whichFigures 1 and 2 illustrate a construction in which there is an operativeconnection between the throttle valve and the movable fulcrum of thelever, Figure l shewing the relative positions occupied by the severalparts when the throttle is closed (or nearly so), while Figure 2 shewsthe positions occupied when the throttle is fully open. Figure 3 shows amodified construction in which the operative connection of the throttleand movable fulcrum is replaced by additional suction apparatus, thearranlgemcnt otherwise being as in Figure 1, anc

Figure 4, to a smaller scale than the fore going, shews the applicationto an engine or the apparatus shewn in Figures 1 and 2.

The ignition device shown at A is pro vided with the usual advance andretard mechanism A connected by a hinged link A with a lever B pivotedat B to a fixed member such as a part F carried by the engine to whichthe invention is applied. A tension spring 13 anchored at one end to aconvenient fixed point F and at the other end connected to a flexiblestrip or the like 13 attached at B to a curved part l3 of the lever B,ensures a substantially constant leverage of the spring throughout therange of movement of the lever B.

In the position shewn in Figure 1, the ignition is in the fully advancedposition, and the spring B acts continually to retard it. This action isopposed by the suction effect in the induction pipe F at a positionbetween the closed throttle F and the cylinders F, such effect beingtransmitted by way of a conduit C to a bellows C anchored at one end Cto a fixed part, and at the other end C connected by a hinged link Cwith a lever D fulcrumed at D to a fixed member. The lever D isarrangedside by side with the lever B, and interposed between them is aroller E, preferably divided into three separate rollers located side byside the middle one E as shown by the broken line being slightly smallerin diameter than the outer ones so that it engages the lever B only,while the outerrollers engage the lever D only, which is there thickenedsufficiently to permit this. The roller is thus engaged by therespective lewhich the roller E occupies relative to thercspectivelulcr' B and D and the amount of suction pertaining; at thetime. Accord ingly, therefore, this roller is mounted at the end of alink E which is operativel connected with the hand control lever F ofthe throttle valve F located in the induo tion pipe F As it is desirablethat the movement of the roller E away from the tulcra B and D should berelatively small at the nearly closed position or the throttle, butshould continually increase in magnitude as the throttle F is opened, atoggle system oi? linkage is employed to effect this, comprising thebell/crank lever G (pivoted to a fixed part) of which one arm G issubstantially parallel with the throttle arm F upon the throttlevalve'F,and is connected with it by a link G The other arm G of the bell "crankle'verconstitute's with the link 13* the toggle mechanism, beingsubstantially in line withit when the throttle is closerhbut approachingor reaching a position at right angles to itjwhen the throttle is fullyopened, Thus it will be'evident that movement of the roller E acting toreduce the spring effect will be very, slight while the throttle ispartly closed, but will be considerably greater when the throttle isfully opened, and consequently (the suction pressure is relativelysmall, the mechanism ensuring that at this position the spring B shall,haveits least effect, or conversely, that the suction shall have itsgreatest er'iect.

To enable independent adjustment of the position of the roller E to suitparticular types of engines and to effect this it necessary whiletheengine is running, the link f has a threaded connection at E with themember by which it is hinged to the arm G of'the bell crank lever G, anyknown or convenient ari'a1'1geinent being provided to ensure that itseffective length is varied when it is rotated. Furthermore to facilitatestarting and to ensure a correct location of the ignition device forthis purpose, a notch maybe provided at B in the lever B so that theroller E will readily engage the notch, and thus ensure the correctposition. The engagement oft-he rollerwith both levers B and D is at alltimes ensured by the spring action and the suction etl'ect which act inconjunction with one another to thrust the respective levers against theroller from opposite sides of it.

The use of the bellows C avoids frictional losses and/or leakages whichare liable to arise if a cylinder and piston are employed, and it alsotends thereby to render the apparatus more sensitive tochangesofpressure.

The disposition of the parts as shown in Figure 2 will be clearlyunderstood from the toregoii'rgdescription of the apparatus, and it willbe partlcularly noticed from this arrangement that although some changeof leverage takes place with the lever D by reason of the movement ofthe roller E, is comparatively slight ascoinpared with the changes ofleverage of the'lever B. If through reduction of load any increase ofsuction occurs with the throttle 't'u open, the increased suction willact to overcome the force of the spring B and will advance the ignitionas is desirable, while any closure oi the throttle, while it acts tomove the roller nearer to the fulcra of the levers B and D, will also atthe same time product-i a decrease of the suction effect which istending to overcome the spring B and to advance the ignition too much. i

From the foregoing description, the modi li'cation illustrated in Figure3 will be read ily understandable, inasmuch as the only changes are inthe Ina-line of controlling the position of the roller E. For this pur-'a link H extending troni'the movahlelwail H of a bellows H constitutingtheadditionai or supplementary suction device. This latter hasits fixedwall at H and from this a conduit H extends to the induction n it :2

to secure by Letters Patent of the United States is 1. In an internalcombustion engine, the combination with the induction pipe and athrottle valve therein, of an ignition timingdevice, a suction ope'rateddevice communicating with the said i'nductionpipe 'so as to advance thesaid timing device with each increase ot suction, a lever systeminterposed between the said suction and timing devices, a springarranged to oppose the suction advance, and means actuated by avariation in the position of the said throttle valve to vary theposition of the fulcra of the said lever system.

2. In an internal combustion engine, the combination with the inductionpipe and a throttle valve therein of an ignition timing device, aninduction pipe, a suction-operated device connected with said inductionpipe and adapted to advance said timing device with increase of suction,a lever actuated by said suction device, a lever connected with saidtiming device, a. displaccable member forming an operative connectionbetween said levers and movable along them to vary their respectiveacting leverages, a spring adapted to oppose suction advance and meansdependent upon the position of said throttle for varying the position oisaid displaceable member connecting said levers.

3. In an internal combustion engine, the combination with the inductionpipe and a throttle valve therein of an ignition timing device, aninduction pipe, a suction-operated device connected with said inductionpipe and adapted to advance said timing device with increase of suction,a lever actuated by said suction device, a lever connected with saidtiming device, a displaceable member forming an operative connectionbetween said levers and movable along them to vary their respectiveacting leverages, a spring adapted to oppose suction advance, meansdependent upon the position of said throttle for varying the position oisaid displaceable member connecting said levers, and a toggle linkagesystem connecting said displaceable member with said means, adapted toproduce an increasing degree of movement of said member as said throttleappreaches its fully open position.

In an internal combustion engine as claimed in claim 3, the combinationwith the displaceable member and the control means therefor, of anadjustable linl; adapted to vary the acting position oi saiddisplaceable member.

5. In an internal combustion engine, the

combination with the induction pipe and a throttle valve therein of anignition timing device, a suction-operated device connected with saidinduction pipe and adapted to advance said timing device with increaseof suction, alever actuated by said suction device, a second lever sideby side with the first-mentioned lever and connected to said timingdevice, a roller located between said levers and displaceable alongthem, a spring acting upon said timing device and said lever connectedtherewith to cause said lever to bear against said roller and hold itagainst the first-mentioned lever, and an operative connection betweensaid roller and the aforesaid throttle valve whereby the leverage ofsaid levers is varied in accordance with the movements of the throttlevalve.

6. In an internal combustion engine as claimed in claim 5, locating thelevers connected respectively with the suction device and the ignitiontiming device, so that when said roller is opposite the fulcrum of theignition advance lever it is at a distance from the fulcrum of thesuction actuated lever.

7. In aninternal combustion engine, the combination with the inductionpipe and a throttle valve therein of an ignition timing device, acontrol lever for said throttle valve, a bellows, a conduit connectingsaid bellows with said induction pipe at a point between said throttlevalve and the cylinder of said engine, means for connecting said bellowswith said ignition timing device, adapted to advance said timing devicewith increase of suction, said means comprising two levers pivot-ed sideby side, one connected with said bellows, the other connected with saidtiming device, a roller located between said levers and displaceablealong them adapted to vary their effective leverages, a spring acting inopposition to the suction of said bellows upon said timing device,tending thereby to retard it and also to compress said displaceableroller between said levers, a toggle link system connecting said rollerand said throttle control lever, adapted progressively to increase theroller move ment along said levers, as the throttle is opened, and viceversa, means for adjusting the position occupied by said roller at anygiven throttle position, and a notch in the lever connected with saidtiming device, located opposite the pivot of the lever con nected withsaid bellows, constituting a location for said roller when said throttlevalve is in its closed position.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

EDWARD DODSON.

\Vitnesses:

STANLEY WV. HUGHES, A. I. ORUMP.

